Variable lobe camshaft



Jam 1970 w. D. SEVERN VARIABLE LOBE CAMSHAFT Filed June 14, 1968 IN VENTOR WLMQU 2 EVIV United States Patent 3,489,032 VARIABLE LOBE CAMSHAFT Willard D. Severn, Yuba City, Calif. (14154 Daventry St., Arleta, Calif. 91331) Filed June 14, 1968, Ser. No. 737,072 Int. Cl. F16h 53/00 US. Cl. 74-568 6 Claims ABSTRACT OF THE DISCLOSURE This invention consists of a hollow camshaft having a plurality of integrally formed cam portions projecting outward therefrom, each integral cam portion is not only U-shaped when viewed from the top, but is also provided with a radially movable cam portion that projects outward through an elongated opening in the aforesaid integral cam portion. Each radially movable cam portion is pinned to a shaft that is located within the aforesaid hollow camshaft. The inside shaft is supported by a plurality of bearings located within the hollow camshaft. This inside shaft is rotated with respect to the hollow shaft by means of a governor (not illustrated), secured to the engine in which this invention is located as part of its operating mechanism. This rotation changes the position of the radially movable cam portion to change the contour of the nose of the cam to a contour that is suitable for the speed at which the camshaft is operating.

This invention relates to internal combustion engines; more particularly, to that part of an internal combustion engine known in the art as a camshaft; and still more particularly, to a camshaft that has a plurality of variable lobes, as will hereinafter be described.

Although I personally call my invention a variable lobe camshaft, the term lobe is applied to the parts of the camshaft that are by most people in the art called cams. It is for this reason that I use the word cam throughout this specification and claims in place of the word lobe with the exception of the title of this invention.

It is well known by designers of internal combustion engines that the camshaft is one of the most important parts of an engine and that the contour of the nose of the cam controls the efliciency of the engine in which the camshaft is located. A contour which gives maximum efiiciency for one speed will not give maximum efficiency at other speeds.

The principal object of this invention, therefore, is to provide a variable lobe camshaft that will automatically vary the radius of its cams as the speed of the engine increases or decreases since the speed of the camshaft is controlled by the speed of the crankshaft of the engine.

Another object of this invention is to provide a variable lobe camshaft that by increasing the overall efficiency of the engine will also increase the life of many, if not all, of its associated parts, for example, the mufiier and the tail pipe.

Still another object of this invention is to provide a variable lobe camshaft of the character herein described that contains a minimum number of parts so arranged as to be foolproof in operation.

Other and further objects of this invention will come to light as the reading of this specification proceeds and the accompanying drawing is examined.

In the drawing:

FIG. 1 is a side view of this invention.

FIG. 2 is a vertically disposed sectional view of this invention, taken along line 22 of FIGURE 1, and viewed in the direction indicated by the arrows.

FIG. 3 is a vertically disposed sectional view of this "ice invention similar to that of FIGURE 2, but taken with the variable cam in a closed position.

FIG. 4 is a vertically disposed sectional view of this invention, taken along line 4-4 of FIGURE 1, and viewed in the direction indicated by the arrows, showing the way that the cam portions fit when placed in contact with each other.

FIG. 5 is a horizontally disposed sectional view of this invention, taken along line 55 of FIGURE 1, and viewed in the direction indicated by the arrows.

In the several views of the drawing, like parts of this invention are indicated by like reference numbers.

The reference number 10 indicates this invention in its entirety.

The invention consists of a hollow camshaft 11 to which is integrally formed an integral cam portion 12 for each of the valves of the internal combustion engine in which this invention is located. Each of the aforesaid integral cam portions 12 is U-shaped, when viewed from the top or in cross-section, as shown in FIGURE 5 of the accompanying drawing. One end of the aforesaid hollow camshafts 11 is provided with an integrally formed mounting plate 13 in which is located two or more tapped openings 14. These tapped openings 14 are for the reception of the cap screws 15 that secure the camshaft by means of its mounting plate to the camshaft gear 16, as is clearly shown in FIGURE 1 of the accompanying drawmg.

A shaft 17, supported by a plurality of bearings 18, is located within the aforesaid hollow camshaft 11. An elongated, radially disposed opening is made in the aforesaid camshaft 11 between the two sides of each of the aforesaid integral cam portions 12 for the reception of the radially movable cam portions 19 that are secured to the aforesaid shaft 17 by means of the pin 20, there being one radially movable cam portion 19 in each of the aforesaid integral cam portions 12, as one can see by looking at FIGURE 1. Each radially movable cam portion 19 can be said to be basically triangular in shape when viewed from the side and to have a slightly larger ramp 21, that blends into the heel at 22, than the aforesaid integral cam portions 12. Looking now at FIGURES 2 and 3 of the accompanying drawing, it will be seen that the inside edge 23 of the radially movable cam portions 19 has a flattened upper surface 24 that is adapted to rest against the cam rest 25 of the integral cam portion 12 of this invention.

The way in which this invention of a variable lobe camshaft works is quite simple. The aforesaid shaft 17 is connected to a governor in such a way that the cam portion 19 (all cam portions 19) are forced open to the position shown in FIGURE 2 of the accompanying drawing when the engine is running at high speed. The cams 19 are in the position shown in FIGURE 3 when the engine is operating at low speeds, thereby providing the cams of the camshaft with the best possible configuration for a given operating condition. Neither the aforesaid governor nor the mechanism connecting the governor to the aforesaid shaft 11 is shown in any of the views of the drawing since this mechanism is not a part of this invention, and will be different for each style of engine.

This invention can be adapted to any internal combustion engine regardless of its size or the kind of fuel it can use. This invention is subject to any changes one may care to make in so long as the changes fall within the scope and intent of the appended claims.

What I now claim as new is:

1. A variable lobe camshaft of the character described, comprising a hollow camshaft having a plurality of integrally formed cam portions thereon; each of the said cam portions being U- shaped when viewed from the top and having a radially movable cam portion therein that projects through an elongated opening in the said hollow camshaft in which is located a shaft to which the said movable cam portions are secured.

2. The invention of claim 1, wherein the said shaft passes through a plurality of supporting bearings located Within the said hollow camshaft.

3. The invention of claim 2, wherein the radially movable cam portions are secured to the said shaft by means of pins.

4. The invention of claim 3, wherein the configuration of the said radially movable cam portions is such that the nose radius of the cams of which they are a part can be changed by the rotary action of the said shaft which is activated by a governor connected to the internal com- :bu stion engine in which the said camshaft is mounted.

5. The invention of claim 4, wherein the upper inside portion of each of the said integrally formed cam portions is provided with a cam rest against which one edge of the said radially movable cam portions will at times rest.

6. The invention of claim 5, wherein each of the said radially movable cam portions has a configuration that is basically triangular having in part a curved periphery.

References Cited UNITED STATES PATENTS FRED C. MATTERN, 111., Primary Examiner F D. SHOEMAKER, Assistant Examiner 

